A kind of method preparing p-phthaloyl chloride
Technical field
The invention belongs to industrial chemicals preparing technical field, be specifically related to a kind of method preparing p-phthaloyl chloride.
Background technology
P-phthaloyl chloride is important Organic Chemicals, namely can be used as medicine, pesticide intermediate, also can be used for high temperature resistant, the high strength polymeric such as synthesis Fanglun l414, polyarylsulphone synthetic fibre, polyester, polyarylester, be widely used in aircraft, rocket, guided missile, suit, special uniform and fire-fighting equipment.
P-phthaloyl chloride can after photocatalysis chlorination, hydrolysis be obtained again by p-Xylol, but the method temperature of reaction is up to 200 ~ 300 DEG C, and energy consumption is high, and product yield is not high.P-phthaloyl chloride also can be obtained through acyl chloride reaction by terephthalic acid, and conventional chloride reagent has sulfur oxychloride, phosphorus trichloride, phosphorus pentachloride photoreactive gas.Be that chloride reagent prepares p-phthaloyl chloride with sulfur oxychloride, Main By product is HCl and SO
2gas, easy and product separation is method conventional at present.The method with DMF or pyridine for catalyzer, 10 ~ 20 hours reaction times, product yield about 85%.But, the method because of DMF unstable, easily and SOCl
2reaction generates vilsmeier reagent, and cause product separation purification difficult, product purity is not high, need carry out repeatedly recrystallization or repeatedly after underpressure distillation product purity just can reach more than 99%.In recent years, bibliographical information is had with immobilized this reaction of quaternary ammonium salt phase transfer catalyst catalysis (Sheng Qingquan, Xiao Jianmou, Liu Taize, chemical reagent, 2009,31 (5), 367), recrystallization after product yield can bring up to 90%, and purity can reach more than 99%, but, the method catalyzer not easily obtains, cost is high, and catalytic activity has much room for improvement.
Summary of the invention
React prepare that catalyst activity in p-phthaloyl chloride is low, cost is high to solve current terephthalic acid and sulfur oxychloride, product need through repeatedly recrystallization or repeatedly after underpressure distillation purity just can reach 99% with first-class outstanding problem, the object of the invention is: develop a kind of cheap and easy to get, to stable high reactivity, the high-selectivity catalyst of sulfur oxychloride, for catalysis p-phthaloyl chloride and sulfur oxychloride reaction, high yield obtains paraphthaloyl chloride with high purity.
For achieving the above object, the technical solution used in the present invention is shown below:
According to the present invention, consider terephthalic acid (PTA) and sulfur oxychloride (SOCl
2) reaction mechanism may as shown in Equation 1, the present invention adopts this reaction of nitrogenous organic base catalysis.On the one hand, suitable nitrogenous organic base is conducive to leaving away of hydrogen in PTA, thus promotes the reaction process of I to II in formula 1.On the other hand, PTA is difficult to be dissolved in SOCl
2equal solvent, reacts for solid-liquid two phase reaction, is difficult to carry out, and the hydrogen ion that nitrogenous organic base and PTA leave away is combined and generates organonitrogen positive ion, and forms ion pair with carboxylate radical II in formula 1, strengthens PTA at polar solvent SOCl
2in solvability, thus PTA is transferred to SOCl
2in react, accelerated reaction is carried out.
Formula 1, terephthalic acid and sulfur oxychloride reaction mechanism are inferred
One or more in the preferred following structural formula of nitrogenous organic base catalyzer of the present invention.R in following structural formula
1be preferably-CH
3or-C
2h
5; R
2be preferably H or-CH
3,-C
2h
5or-N (CH
3)
2, R
2on any carbon on ring except aromatic ring shares carbon; R
3be preferably-CH
3,-C
2h
5or-CN, R
3can on ring on any carbon.
According to the present invention, for making mass transfer in reaction process carry out smoothly, adopt excessive SOCl
2for solvent reduces reaction system viscosity, SOCl
22:1 ~ 5:1 preferred with PTA mass ratio.Nitrogenous organic base catalyst levels is preferably 0.5 ~ 2% of PTA quality, temperature of reaction preferably 70 ~ 120 DEG C, preferably 4 ~ 16 hours reaction times.
According to the present invention, PTA and SOCl
2reaction generates p-phthaloyl chloride can produce HCl and SO simultaneously
2mixed gas.Under considering the same terms, the solubleness of HCl gas in water compares SO
2much bigger, 1 volume water dissolvable 500 ~ 700 volume HCl gas under normal temperature, but about 40 volume SO can only be dissolved
2, HCl and SO that reaction produces by the present invention
2mixed gas first absorbs with water and generates hydrochloric acid, then absorbs generation S-WAT by NaOH solution.
Consider that the nitrogenous organic base catalyzer that the present invention adopts is lower than the boiling point of p-phthaloyl chloride and PTA, the present invention's reaction terminates the excessive SOCl of rear first Distillation recovery
2, catalyzer is reclaimed in distillation or rectification under vacuum, and obtains product p-phthaloyl chloride by rectification under vacuum.The SOCl reclaimed
2solvent and nitrogenous organic base catalyzer is capable of circulation uses again.
Specific practice of the present invention is: by SOCl
2mix with mass ratio 2:1 ~ 5:1 with PTA, add 0.5 ~ 2% catalyzer of PTA quality, be warming up to 70 ~ 120 DEG C of reactions 4 ~ 16 hours, the gas that reaction generates first absorbs with water, then absorbs by NaOH solution, and reaction terminates the excessive SOCl of rear Distillation recovery
2, catalyzer is reclaimed in distillation or rectification under vacuum, and obtains product p-phthaloyl chloride by rectification under vacuum.Product by GC-MS and
1hNMR,
13cNMR carries out qualitative analysis, and purity passes through gas chromatographic detection.
The present invention adopts one or more in the nitrogenous organic base such as substituted pyrrolidin, substituted piperidine, substituted pyridines, (replacement) quinoline, (replacement) isoquinoline 99.9, (replacement) phenanthroline, substituted imidazole, substituted benzimidazole for catalyzer, catalysis PTA and SOCl
2reaction, reaction terminates rear Distillation recovery excess thionyl chloride, catalyzer is reclaimed in distillation or rectification under vacuum, and obtain product p-phthaloyl chloride by rectification under vacuum, yield reaches as high as 96%, purity higher than 99%, have catalyzer cheap and easy to get and capable of circulationly to use again, product yield and the advantage such as purity is high, operation is simple and convenient.
Embodiment
The following example contributes to understanding the present invention, but content of the present invention is not limited thereto.
Embodiment 1
By 100 grams of terephthalic acids (PTA), 300 grams of sulfur oxychloride (SOCl
2) and 2 grams of 1-crassitudes add in 1 liter of round-bottomed flask, stir, be warming up to 100 DEG C reaction 10 hours, HCl and SO of generation
2mixed gas first absorbs with water, then absorbs with 30%NaOH solution, and reaction terminates rear Distillation recovery catalyzer and excessive SOCl
2156 grams, and obtain product p-phthaloyl chloride (TPC) 110 grams by rectification under vacuum, separation yield is 90%.Product by GC-MS and
1hNMR,
13cNMR carries out qualitative analysis, and gas chromatographic detection purity is higher than 99%.
Embodiment 2 ~ 25
The specific practice of embodiment 2 ~ 25 is similar to Example 1, concrete reaction conditions and the results are shown in table 1.
Embodiment 26
By the SOCl that embodiment 1 reclaims
2add in 1 liter of round-bottomed flask with catalyzer, then add SOCl
2145 grams, stir, be warming up to 100 DEG C of reactions 10 hours, HCl and SO of generation
2mixed gas first absorbs with water, then absorbs with 30%NaOH solution, and reaction terminates rear Distillation recovery catalyzer and excessive SOCl
2156 grams, and obtain product TPC110 gram by rectification under vacuum, separation yield is 90%.Product by GC-MS and
1hNMR,
13cNMR carries out qualitative analysis, and gas chromatographic detection purity is higher than 99%.
Can find out according to embodiment 1,1-crassitude can catalysis PTA and SOCl
2reaction preparation TPC, product yield can reach 90%.Embodiment 2 ~ 3 shows that TPC yield also can reach 90% with 1-methyl piperidine and 1-ethyl piperidine for catalyzer.Embodiment 4 does not use catalyzer, does not obtain product TPC, shows that catalyzer plays most important effect to this reaction.Embodiment 5 is attempted with 1-methylpyrrole for catalyzer, result and embodiment 1 contrast known, although with the hydrogenation products 1-crassitude of 1-methylpyrrole for catalyzer can obtain better result, but 1-methylpyrrole can not this reaction of catalysis, this may be because of two double bond generation conjugation on the lone-pair electron on 1-methylpyrrole nitrogen and ring, form an aromatic nucleus, cause its alkalescence too weak, in very difficult promotion PTA, hydrogen leaves away, also be not easily combined with hydrogen ion and form nitrogen positive ion, thus can not catalysis PTA and SOCl
2reaction generates TPC, shows to only have suitable nitrogenous organic base this reaction of catalysis could obtain better result.Embodiment 6 attempts to take carbazole as catalyzer, does not obtain product TPC; Embodiment 7 take DMA as catalyzer, and TPC yield is 83%, also shows that suitable nitrogenous organic base just can obtain better catalytic effect.Embodiment 8 take pyridine as catalyzer, and TPC yield is 85%, and the catalyzer that embodiment 9 ~ 13 adopts is all substituted pyridines, but reaction result difference is very large.When pyridine ring being with electron-withdrawing substituent-Cl, catalytic effect is obviously poorer, and attempting with 2,6-dichloropyridine is that catalyzer does not obtain product TPC.Pyridine ring is with electron donating group-CH
3time, catalytic effect is obviously better.When curiously pyridine ring being with electron-withdrawing substituent-CN, catalytic effect is also better.Embodiment 14 ~ 25 shows, nitrogenous organic base catalysis PTA and the SOCl such as (replacement) quinoline, (replacement) isoquinoline 99.9, (replacement) phenanthroline, substituted imidazole, substituted benzimidazole
2reaction preparation TPC also can obtain better result.Embodiment 26 shows that catalyzer is capable of circulation and uses.Use the catalyzer that the present invention adopts, sulfur oxychloride and PTA mass ratio are preferably 2:1 ~ 5:1, catalyst levels is preferably 0.5 ~ 2% of terephthalic acid quality, temperature of reaction is preferably 70 ~ 120 DEG C, reaction times is preferably 4 ~ 16 hours, product TPC yield reaches as high as 96%, and purity is higher than 99%.
Can find out from above embodiment, the present invention have catalyzer cheap and easy to get and capable of circulationly to use again, product yield and the advantage such as purity is high, operation is simple and convenient.
Table 1, PTA and SOCl
2react reaction conditions and the result of TPC processed
a
a10 grams of terephthalic acids (PTA);
brelative to PTA quality; C is relative to mole separation yield of PTA.
Table 1, PTA and SOCl
2react reaction conditions and the result of TPC processed
a(Continued)
a100 grams of terephthalic acids (PTA);
brelative to PTA quality;
crelative to mole separation yield of PTA.